How did/do natural gas powered refrigerators work?

[bluemoonKY]

My father told me that when he was a child in the 1950s, his parents owned a natural gas powered refrigerator. He said that the refrigerator made no noise when it was running. I can't fathom how a natural gas powered refrigerator would work. I mean, it would make no sense for natural gas to power the evaporator/condenser fans on the refrigerator. If natural gas powered the fans, it would entail natural gas powering a generator to generate the electricity. I think maybe natural gas powered the compressor on the refrigerator. My father thinks that maybe the refrigerator did not have any compressor at all. He thinks maybe the refrigerator cooled food in another way, but neither he nor I have any idea how it would work.

I am not sure, but I don't think that any natural gas powered refrigerators are made any more.

How did/do natural gas powered refrigerators work?

 

[AlephZero]

They are still being made and used. http://en.wikipedia.org/wiki/Absorption_refrigerator

 

[NTW]

Today, small absorption refrigerators are comparatively rare, but they are still being made. Here is a Spanish manufacturer that has been making two models for over 30 years. Most of them for export:

http://www.taver.es/eng/frigorificos.php